LONDON (AP) — Republican presidential candidate Mitt Romney on Wednesday said many of the weapons obtained by the shooting suspect in Colorado were obtained illegally and that changing laws won't prevent gun-related tragedies.

But the firearms that authorities allege James Holmes used to kill 12 people in Aurora, Colo., were obtained legally.

"This person shouldn't have had any kind of weapons and bombs and other devices and it was illegal for him to have many of those things already. But he had them," Romney told NBC News in an interview. "And so we can sometimes hope that just changing the law will make all bad things go away. It won't."

Holmes broke no laws when he purchased an assault-style rifle, a shotgun and Glock handgun, and he passed the required background checks.

Holmes apparently booby-trapped his apartment with explosives. It's unclear if he obtained the materials illegally, but it's against Colorado law to build an explosive device.

NBC News anchor Brian Williams pressed Romney about his tenure as Massachusetts governor, when the presumptive GOP nominee signed a bill that banned some assault weapons like the type Holmes is alleged to have used. At the time, Romney described such guns as "instruments of destruction with the sole purpose of hunting down and killing people."

Asked if he stood by those comments, Romney mentioned the Massachusetts ban but said he didn't think current laws needed to change.

"I don't happen to believe that America needs new gun laws. A lot of what this ... young man did was clearly against the law. But the fact that it was against the law did not prevent it from happening," Romney said.